Hyperspectral imaging in the 8–14 micron region, also known as the thermal infrared or long-wave infrared (LWIR) is assuming increasing importance in military and civilian remote sensing. The day/night capability of LWIR hyperspectral imaging, coupled with its ability to detect camouflaged targets, buried land mines and gaseous chemical agents, make it an attractive reconnaissance tool for military applications. Civil remote sensing benefits from the chemical analytical capabilities of LWIR hyperspectral that complement visible, near-IR and shortwave (VISNIRSWIR) hyperspectral methods. LWIR hyperspectral imaging is more challenging from a sensor design standpoint than VISNIRSWIR instruments because of instrument self-emission and low temperatures required of LWIR photon sensitive focal planes. The power, weight and mass requirements imposed by cooling optics and focal planes raise the initial and recurring cost of systems and limit their applications to platforms that can support the requirements.
Recent advances in uncooled LWIR detector technology, specifically large arrays of microbolometers, have allowed development of uncooled LWIR multispectral imaging systems using relatively broad bands (themis, space imaging). However, the sensitivity of these arrays is insufficient to produce usable true hyperspectral imaging using dispersive or filter techniques. See, Sellar, R. Glenn, Boreman, Glenn D., Kirkland, Laurel E., “Comparison of signal collection abilities of different classes of imaging spectrometers”, in Imaging Spectrometry VIII, edited by Shen, Sylvia S., Proceedings of the SPIE, Volume 4816, pp. 389–396 (2002). It would be desirable to enable true hyperspectral imaging in the LWIR with usable signal-to-noise ratio (SNR).